#include <stdlib.h>
#include <stdio.h>

void main() {
  int n, i, sinal = -1, termo;

  printf("Numero de elementos:\n");
  scanf("%d",&n);
  for (i = 1; i <= n; i++) {
	sinal = sinal * (-1);
	termo = (sinal * (2 * i));
	printf ("%d\n", termo);
  }
}

